1. Field of the Invention
The present invention relates to controlling industrial machinery and, particularly, to setting and controlling apparatus used in bookbinding operations. More specifically, the present invention relates to an improved control system for machinery employed in a bookbinding procedure, the improvement enabling the exercise of control over the machinery in the event of failure of the computer-automated portion of the control system. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Related Art
In recent years, the printing industry has become increasingly dependent on computer-automated control systems for performing a wide variety of functions. One area within the printing industry where computer automation has been successfully utilized is in the controlling of book-binding machinery, For example, computer-based control systems are presently used to store binding machine settings obtained from a lengthy and complex preliminary set-up procedure. With such a control system, once the machine settings have been stored in a computer they can be quickly recalled to assist machine set-up for future operations on books having the same format. By resetting a binding machine according to previously stored format settings, unnecessary duplication of effort can be avoided. Thus, through the use of computer-control, binding machine control systems have dramatically reduced preliminary set-up time and the operation of these machines has been greatly simplified. Consequently, computer-automation of this nature has yielded a reduction in the overall cost of book-binding operations.
Presently, a typical computer-controlled book assembly line generally consists of a plurality of functional stations having components which can be precisely positioned with electromechanical adjusting devices and some form of computer-based control system for controlling the adjusting devices. Each of the adjusting devices includes at least one actuating element for imparting motion to the component to be positioned, and at least one position measuring sensor for detecting the position of the adjusting device. The actuating elements of such adjusting devices typically comprise servo-motors which are operably associated with adjusting spindles for either clockwise or counter-clockwise rotation. Each servo-motor will impart motion to an associated machine component via an adjusting spindle in response to control signals received from the control system. The position sensors directly or indirectly sense the location of the adjusting devices and transmit positional information to the computer for processing and/or storage.
Typically, the control system for a machine employed in a book-binding operation will include a centralized control device and a plurality of local control devices. The centralized control device consists of an operator/system interface, such as a personal computer with a key board and a monitor, and a machine control system, such as an SPS control system. The machine control system is connected between the computer and the adjusting devices for converting digital information received from the computer into currents which will drive the adjusting devices in the appropriate direction. Settings for a given format may be inputted by an operator at a local control device and/or at the computer, and implemented at the adjusting devices via the SPS machine control system.
The type of control system being described, as mentioned above, also customarily has a local control device associated with each adjusting device, the local control devices being connected to the computer via a data bus. These local control devices each typically include an input device to enable an operator to input or change format settings and a display to allow the monitoring of position information from the functional station of the binding machine. Format settings inputted at the local control device are transmitted to, and stored at, the computer of the centralized control device. Alternatively, the computer can receive the settings from the position sensors. The book-binding machine can thus be manually set-up using the local control devices and the position of the components controlled by the adjusting devices will be detected by the position sensors for transmission to the computer.
As noted above, the use of the known recently developed computer-automated control systems has greatly simplified book manufacturing operations. Prior to the use of computer-automated control systems for controlling book-binding machines, preliminary set-up of each functional station of a binding machine was implemented manually. This invariably entailed a lengthy process often involving a substantial amount of trial and error. Most importantly, once a binding machine was reset in preparation of a subsequent binding operation, the time and labor expended to achieve the previous format setting could not be saved for future use. Thus, significant additional expense would have to be incurred to duplicate the previous format settings if needed at a future time. The use of computer-based control systems of the type described above, however, allows laboriously obtained format settings to be stored and quickly recalled to automatically implement repositioning of the adjusting devices. Since settings for a large number of formats can be stored in the computer and repeatedly recalled, substantial time and labor savings can be achieved. Thus, the benefits of automating binding-machine operations include simplified binding machine operation, minimization of binding machine set-up time, and overall cost reduction.
Previously available binding machine automated control systems can create considerable interference with normal book-binding operations in the event of control system failure. For example, employing previously available control systems, appropriate movement of the adjusting devices, and hence movement of the binding machine components, is wholly dependent on proper operation of the control system, i.e., failure of virtually any part of the control system could prevent performance of some vital function. Thus, there has existed a need in the art for an improved control system for use with a book-binding machine which enables an operator to override the computer-based control system and also to utilize alternative means to selectively control individual adjusting devices of the binding machine in the event of failure of the computer-based control system.